SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6595c21523336f8c9bf9ed20ecb5b2e41a1ba637de42f8878d974277b65f6785' 
  AND token = 'huXXOpfi451VVHKX/jU4Q6Qn5eKZrmGlaFfzuF+QfyE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}